Originally Posted by Fish-and-Chips-Yum
Thank you very much for this lengthy post. It was both insightful and very helpful advice. I am also very unsure of the extent of her problems and the help she is/is not receiving, as all I am given are snippets like the ones I quoted in my post. I agree that I should not feel obligated to take on these problems, as I certainly am not equipped to handle such things in the best way possible for her and me. I will likely pull her aside and talk to her, because quite frankly, along with myself not being able to properly give her the help she needs, it's not something my current mental state can bear. I'm hoping that she will understand.
She may not understand, but try not to trap yourself into worrying too much whether she "understands" or "approves". If you need space from this, you need space. If you need space for your own health, that's extremely important that you make that space. I am not sure that pulling her aside will do anything except open you up for some outraged drama or martyred reaction (what I always got from my sister). Perhaps a simple distancing with the explanation "I have stuff going on, not available, sorry".